Patent GB-190008998-A (GB)
Title: Improvements in and connected with Staff Apparatus for Controlling the Traffic on Single Line Railways.
Inventor: SMITH EDWARD WYTHE
Filed: 1900-05-15
Granted: 1901-05-04
Abstract: 8998. Smith, E. W. May 15. Controlling traffic on railways, staff and ticket systems for.- Relates to staff-issuing apparatus of the Webb and Thompson type, such as that described in Specification No. 1263, A.D. 1889. In the present invention, the catch L, which locks the usual notched discs D, is itself normally locked by a lever S, adapted to engage the pin p on the catch. When a staff is raised, it turns the lever S and releases the pin p, so that, if the electromagnet E M is energized by a current in the proper direction, the catch L is disengaged. If, however, the proper current does not pass, the clutch is not raised, and the further movement of the lever S by the staff again locks the catch. The electromagnet EM is arranged as a 'keeper' for the two permanent magnets NS. which, as in a modification, may be bent so that each embraces both poles of the electromagnet. The magnets normally form a closed magnetic circuit, and are carried by the lever shown, the lower arm of which is engaged by an arm on the lever S, the pole-pieces x<1>, x<2> being separated from the armature A on the catch L by brass or other non-magnetic distance-pieces B. A current in the proper direction through the electromagnet causes it and the permanent magnets to attract the catch L, so that, on the magnet-carrying lever being raised by the lever S, the magnets and catch will also be raised to allow the withdrawal of a staff. If a reverse current is passed through the electromagnet, the magnetic circuit between it and the permanent magnets remains closed, and the catch is not operated. A projection d on the lever S is adapted to be engaged by the disc D, to ensure the return of the lever to its normal position. The lever S may also be connected to a cam C, which, during the first position of the movement of the lever, actuates a commutator 3 to connect up the line-wire to the electromagnet EM. Fig. 5 shows another arrangement of the electromagnetic unlocking - mechanism. The armature T is polarized by the permanent magnets N, N<1>, and normally rests against the pole-piece x<2> of the electromagnet EM. When the proper current passes through the electromagnet, the armature is attracted to the pole-piece x<1>, and its hooked end engages the hook H on the catch L, and raises the catch, with the magnets when the latter are raised. The armature is prevented from sticking to the pole-piece x<1> by the fixed piece V engaging the projection W on the armature. The various currents required for the working of the apparatus are produced by magneto-electric generators. One generator is fitted with a commutator to give a direct current for operating the unlocking-magnet, and may also be employed for actuating the code bell, but, preferably, a polarized bell actuated by a second generator giving alternating currents is employed. The two generators may be replaced by a single generator, fitted with additional contacts to produce both single and alternating currents. The polarized bell may also be replaced by a single-stroke bell, actuated by a generator producing direct currents of short duration.